On the other website where you post all your questions you were told:
2 x 18 x W + 2 x 30 x W + 4W^2 = 3/5 x 18 x 30
36 x W + 60 x W + 4W^2 = 324
96 X W + 4W^2 = 324
4W^2 + 96W - 324 = 0
W^2 + 24W - 81 = 0
(W - 3)(W + 27) = 0
W = 3 OR W = -27
Valid answer is W = 3
Then you were told by way of explanation:
The walkway at each side is 30 x W and there are 2 of them
The walkway at top and bottom is 18 x W each so thats 2 bits.
We have so fat counted the sides and top and botton walkways and excluded the bits at the corners.....
That leaves 4 corner squares W x W so thats 4W^2 to add on
Then you said:
Postby Guest » Tue Jul 07, 2015 5:56 pm
I understand it now. Thanks.
You have received the answer to your question and been advised about how the answer is obtained.
Try drawing a diagram.